1. Field of the Invention
The present invention relates generally to filters. More specifically, the present invention is an inlet filter for a high pressure sprayer.
2. Description of the Related Art
There are a wide variety of mechanical devices that require a constant fluid input from a bulk supply. For example, high pressure sprayers are used for many applications. Such sprayers take water (usually) from a low pressure source and pass it through a pump, where a dramatic increase in fluid pressure is achieved. Subsequently, the pressurized water is controllably and selectively dispensed from an appropriate wand or nozzle.
The various components of these sprayers are generally manufactured to high tolerances from a durable material. In use, various valves and connectors are actuated to initiate and then cease the flow of high pressure fluid. This cycling in and of itself produces significant stress on the components of the sprayer and the pump.
Two competing interests exist when designing high pressure sprayers. The components must be strong enough to endure the stresses imposed during use. In addition, the components must be manufactured to interact with one another with a great degree of precision. Often these interacting components are fairly small and intricate. Even the larger components will only have a small margin of acceptable error.
Many manufactures have successfully designed sprayers that will work properly under such conditions. The complicating factor during the actual use of these sprayers is that the water supply is normally unfiltered. For example, in many home and light commercial applications, a garden hose is connected to the inlet of the sprayer. Thus, the water entering the sprayer can be contaminated with varying amounts of dirt or other particles. These contaminates can either be introduced through contamination of the garden hose during other applications, or they are introduced to the water at its source (or through the interconnecting piping) and carried throughout. In any event, a fair amount of contaminates are expected to be introduced to the sprayer and the pump from the water.
As discussed above, with the high levels of pressure involved, the movement of the components, and the required degree of precision in their interaction, it should be readily apparent why the introduction of particulate matter into this system could be destructive. At a minimum, debris may simply clog a nozzle, a port or other orifice. While not necessarily damaging, the system will have to be cleaned, requiring a certain amount of disassembly and down time. More seriously, debris may enter and damage various components in the pump or unloader. Once damaged, these parts will have to be replaced and could be very costly. More specifically, debris in the system can hold open regulation valves in the unloader or regulator or valves within the pump itself. This can cause the system to stop working altogether or it could simply cause it to perform poorly. In addition, such debris will cause these valves and other components to wear prematurely.
In order to avoid the damage caused by contaminates, it has become standard practice to place a filtering device on the inlet side of the pump. Water being introduced into the system is first filtered, removing any particulate material that could otherwise cause damage to the various components. This is, of course, an elegantly simple solution to the above problem. The one drawback is that any given filter will have a limited useful life span. As the filter becomes clogged with particulate matter, it will reduce the volume of water passing through it. If the volume per unit of time becomes too low, it will adversely affect the performance of the pressure sprayer.
To overcome this problem, the filtering element must be periodically inspected and replaced. Generally, the filtering element will be occluded from view; hence, the entire filter must be detached and taken apart to expose the filtering element. Since variations in the quality of the water will occur as well as variations in the frequency of use, it becomes difficult to predict or estimate when the filter element should be checked and/or replaced. Many times the filter is not inspected until a loss in performance is seen, as some operators do not realize the importance of proper filtration. By this time, damage may have occurred to the pump due to cavitation caused by the lack of adequate flow into the pump. Thus, fairly frequent and time consuming inspections must be performed.
Therefore, there exist a need to provide an inlet filter for a pressure sprayer that can provide a readily apparent indication that the filtering element is in need of replacing, without requiring detachment and disassembly of the filter for inspection.